Mechanism for automatic stopping and reversal of electromechanically operated doors



' July i2, 1949. c. OPALEK 2,47611 MECHANISM FOR AUTOMATIC STOPPING ANDlREVERSAL OF ELECTRGMECHANICALLY OPERATED DOORS Filed July '7. 1945 4Sheets-Sheet 1 July 12, 1949. c. OPALEK 2,476,11

MECHANISM FOR AUTOMATIC STOPPING AND REVERSAL OF ELECTROMECHANICALLYOPERATED DOORS 4 sheets-sheet 2 Filed July 7, 1945 July 12, 1949. c.OPALEK A 2,475,111

MECHANISM FOR AUTOMATIC STOPPING AND REVERSAL OF' ELECTROMECHANICALLYOPERATED DOORS Filed July 7, 1945 4 Sheets-Sheet 3 lNVENTOR Chf/:fa Es@PAM-K @Y BLZ@ MM ATTORNEY July 12, N949. c. OPALEK MECHANISM FORAUTOMATIC STOPPING AND REVERSAL OF ELECTROMECHANICALLY OPERATED DOORS 4Sheets-Sheet 4 Filed July 7, 1945 @www awww QW M O CLOSE INVENTORCHARLES OPALE/6 ATTORNEY Patented July 12, 1949 TED STATES OFFICE 12Claims. 1 This invention is related'toiand constitutes lan addition tomys invention disclosed' and'patented IinLettersy Patent Nos.2,3l2;597'v and '25366,948.

In those prior patentsaaredisclosed a` system and mechanism forautomatically leiiecting the I operation of doors, such as garage doors,under they control ofimanual-switches either within or outside thegarage.

Thepurpose of-this invention is to vadd to such system-and mechanismsafety means for avoidiingdamage or injury in case the doors encounteran obstruction during-theirmovement either toward closed. or .openposition.

Preferablythe means of this invention will operate to reversethe powerdevice-if an obstruction is ymet while a door is closingand thus causethepartially closeddoor to return to open position. As a precautionarymeasure in case an obstruction ismet While-'a door isopening, it willordinarilyY suiiice to disable the power device,.as, for example, toopen vthe circuit'of an electric motor and avoid damagingthe motor.

The objects and'a'dvantages of the .invention 'will be understood fromthefollowing description of the 'embodiment-,ofthe invention illustratedin the accompanying drawings, in which Figs. lis a diagram `of theelectrical system.

Fig. 2 is an'elevation, partly in section,"of V the lowerpart'of a'doorequipped with the contacts 3 forming; part ofthe system.

Fig. 3is anenlarged lfragmentary'section on line 3--3 of Fig.'2. Fig. 4lis a 'bottom plan View 'with 'the door frame in section; showing thedoors Open andthe "operating mechanism as'viewedby'one standingf in thedoorway' andy looking up.

Fig. 5 isf-aviewsimilartoFigxl on' an enlarged 'scale and partially insetionfof the operating mechanism `shown 'for the right hand door'infFigdfi.

Fig. y6 isan'elevation, partly'in'section, as in- `dicated onl the line6-6' of'Fig.'5.

Fig. 7 is a sectional elevation'on the'- line "1--1 "ofFig, 5.

Fig. 8 is a View similartoFig. lof the'right 'hand door-andpartcfthe'leftlland door'an'd lthe operating-fmech-anism ltherefor;showingthe fdoors closed.

Fig. 9 is ya detailin'sifdeelevation, indicate'd'by the line 9-9 in Fig.6; ofthe 'reversingswitch--and its support withi the operating links insection.

Fig-10V is an'underside IView of the gearbox and 'cut-outswitchth'ereonand indicating the ipositionof the: parts 1v'when 4-th'e switch isvopen.

ingl the position 'ofthe-parts when the arm has moved substantially `10"-from its extreme open position, allowing theswitch to close.

The invention is shown-as applied Ato swinging doors, but `itfwil-lbeunderstood that it is equally applicable to 4so-ca-llecloverhead doors,that is, doors that articulate sandy slide up and down to 'openandclose.

Primarily ythe illustrated embodiment is -designed to prevent injury toone caught in between the two doors -as their proximate edges approach.each @then-and in theiorrn shownfthe doors are equipped ator-nearftheiry free edges with yieldable rcontacts that cooperate Withfixed contacts on the door to close van electric circuit and` therebyoperate mechanism-that|will reverse the motor. Preferably the yieldablecontacts, such as springs, are covered with a-protective' fabric suchAas leather or rubber.

'-5l having worms' andz'f that mesh with and drive Worm gears 8 andi),"respectively, in their'respe'ctive-gear boxesfliand II. Togglelinkage I2 vconnects the shaftof'worm Wheel' to ydoor2and similarlinkage I3"con`nects'the shaft of Worm wheel 9 with door I; "The motorand the asso- `ciated 'mechanism just ldescribed is' secured on theunderside of thetop of the 'door frame by 4a plate I4 on each end'attached tothe frame by vbosses' or other suitable' means.

Areversible switchl'i ofthe mercury type is 'pivotally mounted'inthedepending arms of an 'inverted U-shape bracketA I6 secured to the samelplate I4 as is the motor 3 and disposedibetween the motora'nd'tliereduction gearing-4y Withits axis at right `angles'to theworm'shaft 5. The

switch I5 is a vquadrupleswitch with'two pairs iolof contact elementsfa,and I5b closed with the switch in one position andtheother two pairs Forreversing the switch it has a lever arm 'I1 on 'site"directionsandactuated by means to be de- Looselymountedonthe shaft 8a of the wormlwheel immediately above the link arm "I2is a Acarri leverIS-haVingS'a'n arcuate slot I'Ba therein into which extends-1aV pin- 2'0on the "arin I2. The

ifoam lever i9 isconnecteid'to-apin-on the lower having a slot intowhich the pin engages so as to permit of the snap over of the switch bythe spring I8. The length of the arcuate slot I9a and the disposition ofthe cam lever I9 relative to the pin 28 are such that the link 2 Ireverses the switch near the end of movement of the arm I2 in bothopening and closing the door.

A magnet 22, which I term a reopen magnet, is also secured on the plateI4 alongside the motor 3 and opposite the switch I5. A pivoted armature23 of the magnet 22 is attached by link 24 to ar pin on the other end ofthe switch arm I1, the link having a slot into which the pin engages soas to permit reciprocation of the switch under the inuence of link 2|,without interference of link 24, under circumstances that will be laterexplained. A relay box 25 may be disposed adjacent the motor, as shown.

The reopen magnet 22 is energized when the doors meet an obstruction ontheir way shut, and the magnet then operates to reverse the switch andthus reverse the motor and open the doors. This can occur, of course,only when the arm I2 and hence the pin 28 has moved sufficiently fromthe extreme open position to allow the cam lever I9 to turn as much asthe reversal of the switch requires. Consequently I provide a cut-outswitch 25 also under the control of the pin 20 which opens and closescontacts in the control circuit for the reopen magnet, as will appearfrom the wiring diagram later to be explained. The switch 25 is pivotedon an adjustable plate 2E on the gear box Ill, immediately above the camlever I9, and the pin 20 extends up through the slot 19a far enough toengage the end of the switch, as shown in Figs. and 6.

The control of this switch by the arm I2 is especially shown in Figs.and 11, from which it will be seen that the pin 20 engages the member 25and opens the switch in the extreme open position of the door,substantially within the angular distance of 10 from the open lineposition of the arm I2. A coil spring 26 urges the member 25 in thedirection to close the switch.

Both doors have a metallic contact strip 2'I, the two strips beingelectrically connected in parallel into one side of a reopen relaycircuit which functions in a manner to be described. Both doors alsohave secured over the lower portion of their free edges an angle plate28' which covers the edge and overlaps the inner face of the door, thetwo plates being electrically connected in parallel to the common returnlead of the reopenl relay and of a stop relay, as will appear. Also bothdoors have on their outer face a contact plate 29, adapted to makecontact with the angle plate 28 when, for example, engaged by arelatively stationary body as the door opens, but normally held out ofcontact by springs 30, as particularly shown in Fig. 3. The two plates2-9 are connected in parallel to one side of the stop relay.

Spring contact members 3| and 32 are vertically disposed on each dooropposite and extending the full height of the plate 28 but insulatedtherefrom and normally out of contact therewith but positioned to bepressed into contact with the plate 28 when either spring engages arelatively stationary bodyas the door is closing. The two springcontacts are connected to the contact strip Z'I, and they are protectedby a leather or rubber covering 33.

The safety features of the system to which this invention relates areengrafted upon the door operating system which is shown in the diagramof Fig. 1 and in the main is the same as that shown and described in mysaid prior patents. It will, therefore, not be necessary to explain indetail that much of the system as is common to the disclosure of myprior patents.

The master control relay 34 is energized from the secondary oftransformer 35 when either one of the button contacts 36a, 36h and 36ois closed, through lead 31, normally closed armature contact 38 of thestop relay 38, lead 40, secondary winding of the transformer, lead 4I,winding of relay 34 and lead 42 back to the other side of the buttoncontact.

This energizing of relay 3'4 attracts its armature 34a and thus closescontacts with normally open contact members 43a and 44o in circuit withthe windings of motor control solenoids 43 and 44, respectively, throughreciprocal cut-out switches 43h and 44h arranged, as shown, so that eachsolenoid when energized opens the circuit for the other solenoid. Thusthe energization of relay 34 sets up the circuit for one or the other ofthe solenoids 43 and 44 depending upon the position of the switch I5.However, the circuit for the motor control solenoids 43 and 44 is shortcircuited at po-ints X and Y as long as the button contact is heldclosed.

The solenoid 43 acts to energize the motor 3 in a direction to close thedoors, and the solenoid 44 acts to energize the motor in a direction toopen the doors. Switch element I5b is in circuit with solenoid 43, andswitch element' I5d is in circuit with solenoid 44. Therefore, when theswitch I5 is in the position shown in Fig. 1 and the armature 34a is up,the circuit of the closing solenoid is closed from the transformerthrough wire 4I, winding of relay 34, armature 34a, movable contact 43a,wire 45, contact 44h, winding of solenoid 43, wire 46, switch element|527, common return 41 to point Y, and thence to armature 38 and wire4i! back to the transformer.

With the switch I5 reversed and the armature 34a up, the circuit of theopening solenoid 44 is closed from point X and armature 34a back topoint Y through movable contact 44a, wire 48, contact 43h, winding ofsolenoid 44, wire 49, switch element I5d and common return 4'I.

Each solenoid 43 and 44 controls three armature operated contacts whichdetermine the direction in which the starting coil 3a of motor 3 isconnected across the supply line 50 and also effect the connection ofthe running coil 3b across the line. Also the closing solenoidcooperates in control of the energization of the reopen magnet 22.

The solenoid 43 actuates three contact armatures 43o, 43d and 43e, andsolenoid 44 actuates three contact armatures 44c, 44d and 44e. The iixedcontacts for armatures 43e and 44e are both connected with the same sideof the line, but the fixed contacts of the other two armatures of thetwo solenoids are respectively connected to opposite sides of the line.The leads of the running coil of the motor are connected, one to oneside of the line and the other to the armatures 43e and 44e, the fixedcontacts of which are connected to the other side of the line. One leadof the starting coil is connected to armatures 43d and 44d, and theother lead is connected to armatures 43e and 44o. Therefore it isevident that the switching from one solenoid to the other reverses thestarting coil but merely continues the energization of the running coil.Hence the direction of operation of the motor depends upon whichsolenoidis energized and therefore uponthe` position of the switch.

disclosedin my'prior patents, this system also employs a fourth relay 5Iwhich I term the reopen relay. This relay controls l:four'contactarmatures, the contacts of three of which are normally open and thefourth of which isI normally closed,v and this relay is energized when aspring contact 3l or 32 is causedto'engage plate 28- and the switch I5is in closing position as shown in Fig. 1, the circuit being closedasfollows: spring contact'3lf-or 32, wire 52, winding of relay 5l,contact 25, wire 53, 'element [5a of the switch, common return 41,contact 38, wire 40,'-transformer 35,1Wire 4|,backcontact 54 controlledby relay-34, wire 55andwire 56 back to the plate 28. This attractsarmature 5I-a and closes a'short across points X -and'Y through`wire'5'i, armature contact Sla andnwire 58. The closing solenoid 43 isthus short circuited and the motor circuit is broken, while relay-Mdskept energized.

. At the same time relayf5l attracts armature-5H) and closes a holdingcircuit' for. itself4 as follows: from the transformer through wire 4I,ycontact 54, wire 55, contact 5H), winding of relay 15|, switch 25, wire53, switch'element 15a, return wire 41, contact 38 and'wire-40 back totheftransiormer. Hence relay 5ll stays energized until the switch'visreversed, whether `or not'the spring contact z is longer held againstplate 28.

Relay 5l valso attracts armatures 5lc and 5|d, the former closing acontact yof the reopen magnet- 22 and connecting one side of the magnet.to one side of the line through wire 59, contactw5flc and wire 60.

Armature 5 l d is the movable `part of .a normally closed contact inthe-lead which provides the connection between one side of the motorstarting coil 3a and .the armature contacts 43d.and 44d. Hence when therelay 5| is energized the circuit for the starting coil is broken atcontact 55d.

The other side of the starting coil is connected to wire 6l whichconnects the side of the reopen magnet 22 opposite its connection towire' 60, with a centrifugal contact 62 that breaks contact with thecommutator when the motor is running and makes contact when the speedfalls'Y below a certain value. The commutator is connectedby wire 63 tothe armatures 43e and 44C.

Now it will vbe seen that when armature-*51e is attracted and the motoris at rest or below acertain speed so that centrifugal contact BZ'isclosed, the reopen magnet is connectedacross the 'line through wire 59,contact 5Ic, wire (il),` coil 22', Wire 6I, contact 62 includingl thecommutator, wire G3, armature 43C, afront contact Ifor-armature 43e andwirer 64 tothe other side of the'line.

The operation of the safety feature may-now be followed. It will beassumed that the switch-fis in thev closing position shown in Fig. 1 andthat-a button has been pushed to'V close the door, thus setting up thecircuit of closing'solenoid 431 and starting the motor in the directionto closethe door, as above explained. Then it willbe assumed that oneAof the doors `on its closing movement encounters an obstruction so asto deflecty one of the-safety spring contacts against plate 28.

'I'his energizes reopen' relay 5| through the circuit above traced. Thiscloses the holding circuit through contact 5 lb and also short circuitspoints X and Y through closing of contactv 54a. -It also closes theconnection through contact v5lc be v` tweennonef side-ot reopen magnet,22:.and onezside of; the `Iline.

. .iT-he @short',circuitsbetween szpoints X and Y deenergizestheaclosingsolenoids43'1and releases g; its'. contacts; thus.'stoppingthegmotor..'lhe'cen-v tr-ifugal contact2f82f isz therefore closed `andw theycircuit offthereopenmagnet isithus oloseduto the other.` sidecof. thenline. "The startingcoil. is not olosed;however;rbeingr open? at`contact 5 Id so long asf` relay? 5 Iz. isf energized.

The-.aboveassumes that theldoorl hadclosed far enoughlfromits?fullyf-openfv position to effectzfa closing of switch 25,otherwise.'ofcoursefthevcircuitf-of; relayY 5I -wouldz not, haveY beenVcompleted.

The energizing of. magnet.' 22: cau-ses they arma-A ture 23 `torbaattractedfwhch` reverses the switch anndithrowsz-itf over `to openingposition. This setsriup'f the: circuiti for: :openings solenoidl 44,lthe master-'relay 34 `beingrenergizedand holding contact 44a'. :inatheffcircuit as long ,asf the `short circuit-between lpointsbX andiY-Hcontinues. The reversal` ofi the'fswitchifb-reaks' the circuit''of-relay 5I,ffbutilthe;release of: contactc-5lla `is timed: so aswto:lsucceed: the closing of: theicircuit-v for solenoid y4.4, vand hence theenergiza'tionof relay 34iar1d:` theconrtinuingwof contact 44a linthercircuit is `not.interr1.-1pted.

V 'I3he .opening =of 'the'circuitforf the .reopenl relay.: 5lrremovesthe 'short4v from" the circuit through thezopening solenoid'.44. It Valso effects the closing ofthe startingcoil circuitat' contact5'-d,witl`1 the result that' the :motors-promptlyl starts `intheotherrfdirection and moves'` the' door-toward Iopen position away from'the lobstruction.

The plate 29 and the stop-solenoid 39=oper ate toistopthe'motorlwhen anobstruction is encounteredduring2 the'fopenirigv movement ofy the door.lDurring'thatTmovernent the switch isrin the-.opposite positionfromvvthat shown. Then -if plate29' isfmadeto contact plate 28 the circuitthrough-f solenoid 'i 39"r -is-=close'd as follows: from plate29ffthrough wire 65,r coil 39,'wire B6, switch elementi e; return wire'41, contactI 38, wire 45, the transformer coil,-fwire4 I, contact'54,wirei 55 and wirev'back to plate 28.

'This attra'ctsarmature38 and breaks the circuit' of 'relay' 3'4.Incidentally it breaks thev circuit f theY` stop' solenoid 3'9alsofbutthe return of-` armatu-re'l38 is' timed so `thatrelay34 issurely deenergized.

fflt'is' obvious that 'changes may bey made `in the construction'f'shown in] the drawings and above particularly described'fwithinf theprincipleA and sooner-of the invention.

The combination-of a door," a kreversible electricwmot'or l" and' ymeansconnected therewith to operate ythef'door,-a -sourcev of'felectricpower, a reversible-switchoperated by the said connected 60 means andarranged to connect the motor` selectively=in=reversedirections tothesource of power, an felectroemagn'e'ticpower device connected ltothereversible-"switch and operative when'energizedhto-zrnovef theyswitch' from itsV closing lposi- 65 tionV toits opening'positior'r arelay vin control of the i-power ldevice, andimeans for Venergizing therelay including normally' "open, contact elements carried bythesdoorfandadapted to `be closed-by engagernent:with al relatively stationary body.

f2. Ther-combination vof a1 door, a reversible electric'motor. andimeans' connected therewithf to' operatethe door,` a source offelectricpower, `a'. reversible4 switch'. operated: by the; saidk connectedvmeans: and A arrangedI to connect .the :motor selec- .75 tively :inreversedirections toi-the source.' of fpower, an electro-magnetic powerdevice connected to the reversible switch and operative when energizedto move the switch from its closing position to its opening position, arelay in control of the power device, a circuit adapted to connect therelay with the source of electric power including normally open contactelements carried by the door and adapted to be closed by engagement witha relatively stationary body, a normally closed cut-off switch in saidcircuit, and means operated by the said connected means near the limitof the opening movement of the door to open the cut-olf switch.

3. The combination of a door, a reversible electric motor and meansconnected therewith to operate the door, a source of electric power, areversible switch operated by the said connected means, a pair ofsolenoids having corresponding ends connected respectively to oppositesides of the switch and -having their other ends connected in parallelto a common lead connectible to the source of electric power, reversingcontacts controlled respectively by the solenoids and adapted to connectthe motor selectively in reverse directions to the source of power, ashunt circuit connected across the solenoids and adapted when closed toshort circuit the solenoids and including a normally open contact, arelay adapted when energized to close the said contact, and means forconnecting the relay in circuit with the source of power, said meansincluding the reversing switch and normally open contact elementscarried by the door in position to be closed when engaged by arelatively stationary body as the door is closing.

4. The combination of a door, a reversible electric motor and meansconnected therewith to operate the door, a source of electric power, areversible switch operated by the vsaid reversing means, a pair ofsolenoids having corresponding ends connected respectively to oppositesides of the switch and having their other ends connected in parallel toa common lead connectible to the source of electric power, reversingcontacts controlled respectively by the solenoids and adapted to connectthe motor selectively in reverse directions to the source of power, ashunt circuit connected across the solenoids and adapted when closed toshort circuit the solenoids and including a normally open contact, arelay adapted when energized to close the said contact, means forconnecting the relay in circuit with the source of power, said meansincluding the reversing switch and normally open contact elementscarried by the door in position to be closed when engaged by arelatively stationary body as the door is closing, a normally closedcut-off switch in the relay circuit, and means operated by the door nearthe limit of its opening movement to open the cut-01T switch.

5. The combination of a door, a reversible electric motor and meansconnected therewith to operate the door, a source of electric power, areversible switch operated by the said connected means, a pair ofsolenoids having corresponding ends connected respectively to oppositesides of the switch and having their other ends connected in parallel toa common lead connectible to the source of electric power, reversingcontacts controlled respectively by the solenoids and adapted to connectthe motor selectively in reverse directio-ns to the source of power, ashunt circuit connected across the solenoid-s and adapted when closed toshort circuit the solenoids and including a normally vopen contact, arelay adapted when energized to close the said contact, meansy forconnecting the relay in circuit with the source of power, said meansincluding normally open contact elements carried by the door in positionto be closed when engaged by a relatively stationary body as the door isclosing, a reopen magnet connected to the reversing switch and operativeto move the switch from its closing position to its opening position,and an energizing circuit for the magnet including a normally opencontact adapted to be closed by the relay.

6. The combination of a door, a source of electric power, a reversibleelectric motor and means connected therewith to operate the door, areversible switch arranged to connect the motor selectively in reversedirections to the source of power, a reopen magnet including anarmature, a lost motion connection between the armature and the switchadapted to allow the switch to reverse freely when the armature isunattracted and to move the switch from closing to opening position whenthe armature is attracted, a pivoted lever having operative connectionwith the switch, means operated by the said connected means toreciprocate the lever at the limits of movement of the door and thusreverse they switch, a relay in control of the reopen magnet, and meansfor energizing the relay including normally o-pen contact elementscarried by the door and adapted to be closed by engagement with arelatively stationary body.

'1. The combination of a door, a Source of electric power, a reversibleelectric motor and means connected therewith to operate the door, areversible switch arranged to connect the motor selectively in reversedirections to the source of power, a reopen magnet including anarmature, a lost motion connection between the armature and the switchadapted to allow the switch to reverse freely when the armature isunattracted and to move the switch from closing to opening position whenthe armature is attracted, a pivoted lever having operative connectionwith the switch, means operated by the said connected means toreciprocate the lever at the limits of movement of the door and thusreverse the switch, a relay in control of the reopen magnet, a circuitadapted to connect the relay with the source of electric power includingnormally open contact elements carried by the door and adapted to beclosed by engagement with a relatively stationary body, a normallyclosed cut-off switch in said circuit, and means loperated by the saidconnected means near the limit of the opening movement of the door toopen the cut-off switch.

8. The combination of a do-or, a reversible electric motor and meansconnected therewith to operate the door, a source of electric power, areversible switch operated by the said connected means, a pair ofsolenoids having corresponding ends connected respectively to oppositesides of the switch and having their other ends connected in parallel toa common lead connectible to the source of electric power, reversingcontacts controlled respectively by the solenoids and adapted to connectthe motor selectively in reverse directions to the source of power, anormally closed stop switch in the common lead, a stop solenoidoperative when energized to open the stop switch, and'a circuit forconnecting the stop solenoid to the source of power including thereversing switch and a normally open contact member carried by the doorand adapted to close the circuit when engaged by a relatively stationarybody as the door moves.

9. The combination of a door, a reversible electric motor and meansconnected therewith to operate the door, a source of electric power, areversible switch operated by the said connected means, a pair of motorcontrolling solenoids having corresponding ends connected respectivelyto opposite sides of the switch and having their other ends connected inparallel to a common lead connectible to the source of electric power,reversing contacts controlled respectively by the motor controllingsolenoids and adapted to connect the motor selectively in reversedirections to the source of electric power, a normally closed stopswitch in the common lead, a stop solenoid operative when energized toopen the stop switch, and a circuit for connecting the stop solenoid tothe source of electric power including the reversing switch and anormally open contact member carried by the outer face of the door andadapted to close the circuit when engaged by a relatively stationarybody as the door is opening.

10. The combination of a door, a reversible electric motor and meansconnected therewith to operate the door, a source of electric power, areversible switch operated by the said connected means, a pair of motorcontrolling solenoids having corresponding ends connected respectivelyto opposite sides of the switch and having their other ends connected inparallel to a common lead connectible to the source of electric power,reversing contacts controlled respectively by the motor controllingsolenoids and adapted to connect the motor selectively in reversedirections to the source of electric power, a normally closed stopswitch in the common lead, a stop solenoid operative when energized toopen the stop switch, a circuit for connecting the stop solenoid to thesource of electric power including the reversible switch and a normallyopen contact member carried by the outer face of the door and adapted toclose the circuit when engaged by a relatively stationary body as thedoor is opening, a shunt circuit connected across the motor controllingsolenoids and including a normally open contact, a relay adapted whenenergized to close the said contact, and means for connecting the relayin circuit with the source of power, said means including the reversibleswitch and normally open contact elements carried by the door inposition to be closed when engaged by a relatively stationary body asthe door is closing.

11. The combination of a door, a reversible electric motor and meansconnected therewith to operate the door, a source of electric power, areversible switch operated by the said connected means, a pair of motorcontrolling solenoids having corresponding ends connected respectivelyto opposite sides of the switch and having their other ends connected inparallel to a common lead connectible to the source of electric power,reversing contacts controlled respectively by the motor controllingsolenoids and adapted to connect the motor selectively in reversedirections to the source of electric power, a normally closed stopswitch in the common lead, a stop solenoid operative when energized toopen the stop switch, a circuit for connecting the stop solenoid to thesource of electric power including the reversible switch and a normallyopen contact member carried by the outer face of the door and adapted toclose the circuit when engaged by a relatively stationary body as thedoor is opening, an electromagnetic power device connected to thereversible switch and operative when energized to move the switch fromits closing to its opening position, a relay in control of theV powerdevice, and means for energizing the relay including the reversibleswitch and normally open contact elements carried by the door andadapted to be closed by engagement with a relatively stationary body.

l2. The combination of a door, a reversible electric motor and meansconnected therewith to operate the door, a source of electric power, areversible switch operated by said connected means, a motor controlcircuit for controlling the connection of the motor to the power sourcecontrolled by the reversing switch and including a normally closedcontact, a stop solenoid operative when energized to open the normallyclosed contact, and a circuit for connecting the stop solenoid to thesource of electric power including the reversible switch, and a normallyopen contact member carried by the outer face of the door and adapted toclose the circuit for the stop solenoid when engaged by a relativelystationary body as the door is opening.

CHARLES OPALEK,

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,574,197 Hynes Feb. 23, 19261,642,317 Webb Sept. 13, 1927 1,682,254 Rorabacher Aug. 28, 19281,745,990 Goldman Feb. 4, 1930 2,253,170 Dunham Aug. 19, 1941 2,342,597Opalek Feb. 22, 1944

